A connection device of this type is known from EP 1 845 299 B1. It comprises a housing into which the insertion section is able to be inserted. The known connection device has, in addition, a blocking element by which the insertion section, inserted into the housing, is able to be locked in the housing. For locking the insertion section in the housing, the blocking element engages into the outer groove of the insertion section and into an annular inner groove formed in the housing. Through a housing opening, the blocking element is able to be withdrawn substantially tangentially to the grooves from the latter. In addition, the blocking element is able to be pre-fitted in the inner groove and in the pre-fitted state permits, with elastic deflection, the inserting of the insertion section into the housing, wherein then the blocking element engages into the outer groove. Furthermore, in the connection device, the blocking element is secured in the pre-fitted state on the housing against a displacement in the peripheral direction.
Furthermore, in the known connection device, the blocking element is equipped with a band-shaped core and a plurality of teeth arranged adjacent in the peripheral direction along the core, which respectively have an outer tooth section interacting with the inner groove in the inserted state and have an inner tooth section interacting with the outer groove in the inserted state. These inner and outer tooth sections protrude from the core on opposite sides, wherein the core, at least between adjacent teeth has in cross-section a core profile which has a principal direction determined by a maximum diameter, whilst the teeth in cross-section respectively have a tooth profile which has tooth principal direction determined by an inner flank of the teeth lying radially on the interior. In the known connection device, the core principal direction and the tooth principal direction run parallel to each other.
Further connection devices which comprise a housing, an insertion section and a blocking element are known for example from U.S. Pat. No. 6,179,347 B1 and from U.S. Pat. No. 3,6060,402.